Workarounds or Tricks to parse greater than 4000 group members

We are doing email merge reminders that exceed the 4000 member maximum in groups so we hit the limitation of bulk merges and must break these groups up into smaller multiple groups and perform multiple email merges. We have an email campaign domain setup but this seems to only remove the campaign limitation of 10,000 per campaign. We fully utilize the email campaign quota for things we care about tracking. We use email merge mostly for reminders of upcoming events, etc.

Was wondering if anyone has come up with a unique way of working around this method. For example:

1. some way to quickly split groups into 4000 member chunks (right now that is a tedious manual effort since there is no counter or other way of creating a saved search to limit the count to under 4000 that I'm aware of - or to create a secondary saved search that starts at 4001 and continues...)